OCR A: AS Further Mathematics: Mechanics (paper 3) 20th May 2019

Here's the exam discussion for the Mechanics AS paper on the 20th of May.

Good luck everyone! Feel free to share any revision tips.

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Reply 1

Loci Pi

Anyone taking this exam later? :smile:

Reply 2

Ramzy12344

How did u guys find it? I thought it was alright except the last 2 questions

Reply 3

CharlieWilde1

Much harder than last year's, this years set of papers were all harder unfortunately.

Reply 4

seabasssss

Did you all find 6A unsolvable as you didn’t know the speed of B after collision with wall due to it not telling you coefficient of restitution? Later used answer to 6B to help but didn’t get 1/2u

Reply 5

Ramzy12344

Yes my friend put the coefficient as 1 and it worked but it didn’t say in the question that the wall was perfectly elastic

Original post by seabasssss

Reply 6

Masterchief1345

Original post by seabasssss

If you wrote the velocity after collision with wall as -eu, then did a second momentum between A and B after collision with wall and also did a second coefficient of restitution, you’d find that by rearranging one of them as eu=...., then substituting it into the other, the velocities of A would cancel and you’d just be left with velocity of b with u only.

Reply 7

theicsmmedic

I found it okay and i thought it would be a nice paper and then I saw the last question where I couldn’t solve 6A and got so confused :///

Reply 8

theicsmmedic

Do you think the overall grade boundaries will stay the same? I just want them not to increase significantly as I think I’ve done enough according to last years boundaries but you never know

Reply 9

Loci Pi

Did anyone find it slightly harder than last year? I think I did alright except the the very last question.

Reply 10

Loci Pi

Original post by Ramzy12344

How did u guys find it? I thought it was alright except the last 2 questions

That's exactly what I thought about the paper :smile:

Reply 11

Loci Pi

Original post by sarunthan87

Do you think the overall grade boundaries will stay the same? I just want them not to increase significantly as I think I’ve done enough according to last years boundaries but you never know

Yeah same here - if the boundaries are similar to last year then it should hopefully be an A.
Hard pure, easier stats, and similar, maybe slightly harder mechanics, could mean the boundaries are the same or slightly lower hopefully :smile:

I spent ages on the last question and then I got frustrated that I had to stop it otherwise I'd run out of time haha! Hopefully OCR are lenient on the method marks for that one!

Reply 12

theicsmmedic

Original post by Loci Pi

I spent ages on the last question and then I got frustrated that I had to stop it otherwise I'd run out of time haha! Hopefully OCR are lenient on the method marks for that one!

I wrote 400 instead of 4000 into my calculator at one stage which cost me 3 marks :frown:

but I hope the boundary for an A on that paper isn’t above 35 as that is a nice boundary from last year - It seems like I’m the only one who found pure the best and mechanics the worst (always was going to be the case as mech is my worst area)

I’m working at 130 for an A so I think fingers crossed it should be fine!

Reply 13

Loci Pi

Original post by sarunthan87

I wrote 400 instead of 4000 into my calculator at one stage which cost me 3 marks :frown:

I found Stats the best and Pure the worst lol! Mechanics is my worst area of maths but I focused most of my revision on it. I think the boundary will be similar to last year for Mechs and Stats but lower for Pure.
My predictions for boundaries are:
42 for Pure
45 for Stats
37 for Mechs
So overall similar to last year hopefully :smile:

I made so many mistakes on Pure from reading numbers in the question wrong. Like for one of them I read 0.001 as 0.01, and I read 12 as 6 somehow???

But I guess all we can do now is hope for the best and hope that the boundaries are low :smile:

Reply 14

Loci Pi

Anyone remember what they got for the dimensional analysis? I got gamma as 0 but I can't remember what I got for alpha or beta.

Reply 15

Masterchief1345

Original post by Loci Pi

Anyone remember what they got for the dimensional analysis? I got gamma as 0 but I can't remember what I got for alpha or beta.

Yeah I got gamma as 0 and I think I got alpha and beta as both 1/2. Then for the next part what was the answer for the scale factor increase for experiment A?

Reply 16

Loci Pi

Original post by Masterchief1345

Yeah I got gamma as 0 and I think I got alpha and beta as both 1/2. Then for the next part what was the answer for the scale factor increase for experiment A?

I think i remember getting 1/2 or something so hopefully it's right! thank you :smile:

Reply 17

theicsmmedic

Original post by Masterchief1345

Yeah I got gamma as 0 and I think I got alpha and beta as both 1/2. Then for the next part what was the answer for the scale factor increase for experiment A

I think I’ve missed something - I got the same alpha and gamma but I got beta as -0.5 as it was like -alpha-3beta+gamma=1 or something

Reply 18

Loci Pi

Original post by sarunthan87

I think I’ve missed something - I got the same alpha and gamma but I got beta as -0.5 as it was like -alpha-3beta+gamma=1 or something

No that's what I got too. If I remember rightly I got:
alpha = 1/2
beta = -1/2
gamma = 0

then my equation was:
wave speed = p^(1/2) * density^(-1/2) or something like that.

(edited 4 years ago)

Reply 19

theicsmmedic

Original post by Loci Pi

No that's what I got too. If I remember rightly I got:
alpha = 1/2
beta = -1/2
gamma = 0

then my equation was:
wave speed = p^(1/2) * density^(-1/2) or something like that.